This invention relates generally to catheters and guidewire deployment of catheter-based treatment tools. More specifically, the invention relates to an occlusion catheter with a distal valve.
Minimally invasive intravascular procedures are revolutionizing many surgical specialties including cardiac surgery, and are becoming common in the treatment of vascular disease. Today, balloon angioplasty is commonly used to alleviate stenotic lesions in blood vessels, thereby reducing the need for heart bypass operations. Medical balloon catheters also have been proven efficacious in treating a wide variety of blood vessel disorders such as intravascular restrictions due to atherosclerosis or restenosis.
Vascular stenoses, which may be partially or totally occluded, are often characterized by having a mineral component. A variety of different protocols have been developed for treating vascular diseases with these calcified areas. The treatment methodologies generally involve mechanically removing or reducing the size of the stenosis, mechanical debridement, atherectomy, balloon angioplasty, stenting, and bypass surgery procedures.
In exemplary intravascular procedures, a balloon catheter dilates an intravascular restriction, or an atherectomy catheter removes the restriction. Unfortunately, the intravascular procedures associated with these devices may result in embolic particles being dislodged while the restriction is dilated or cut. In addition, the dislodged embolic particles may move downstream from the area of restriction and cause another embolism to form, which, in turn, could compromise the flow of blood to the surrounding tissue.
In response to this problem of dislodged particles, occlusion balloon catheters and aspiration catheters have been developed to help prevent dislodged embolic particles from entering the blood stream. The occlusion balloon catheter blocks or impedes blood flow while the aspiration catheter aspirates and removes embolic particles from the area of the stenosis.
Proposed aspiration methods that use an aspiration catheter are described in xe2x80x9cMethods for Reducing Distal Embolizationxe2x80x9d, Imran, U.S. Patent Publication 20030055398 published Mar. 20, 2003. One method crosses the stenosis with a guidewire while aspirating blood, so that blood flows past the stenosis and emboli debris are removed, after which the primary treatment of the stenosis can begin. Another method, which treats a vessel stenosis, involves advancing a guidewire and a first catheter to a location near the stenosis, aspirating particles through the lumen of the first catheter; delivering a therapy catheter to a location near the stenosis; and performing treatment on the stenosis using the therapy catheter.
Occlusion balloon catheters are usually used in conjunction with other catheters, particularly an aspiration catheter. An occlusion catheter, which often includes an elongated shaft and a distally mounted occlusion or attenuation balloon, typically extends through a lumen of a primary dilation or atherectomy catheter. The balloon is advanced through a vessel, positioned distal to the site of the stenosis, and temporarily inflated to prevent embolic particles from flowing downstream as the occlusive restriction is being dilated or cut. After the restriction has been treated, the primary catheter can be removed from over the guidewire of the occlusion balloon catheter. An aspiration catheter can then be advanced proximal to the stenosis to reduce or eliminate the blockage by aspirating the treatment site. Once the embolic particles have been aspirated, the occlusion balloon is deflated and removed from a patient.
An exemplary occlusion catheter and associated occlusion and aspiration method uses a catheter and a guidewire having a hollow shaft and a flexible, shapeable guidewire distal tip. A deflated elastomeric occlusion balloon is located at the proximal end of the distal tip of the guidewire. The distal tip of the guidewire and the balloon crosses the lesion, an inflation device is attached to the proximal end of the catheter, and the occlusion balloon is inflated with dilute contrast agent. Following the inflation of the balloon, an angiogram using fluoroscopy may be taken to ensure complete occlusion by the balloon. The hollow guidewire can be used to infuse or deliver fluoroscopic material or therapeautic agents to the treatment site. The inflation device can be removed from the proximal end of the wire while the occlusion balloon remains inflated, and then a stent-delivery catheter maybe exchanged to provide percutaneous transluminal angioplasty. With the occlusion balloon inflated, balloon angioplasty or stenting may be performed. The embolic particles that are released during a coronary angioplasty or stenting procedure remain trapped in the artery upstream of the occlusion balloon. Following the removal of the angioplasty balloon catheter, an aspiration catheter may be introduced over the guidewire to aspirate the particles.
A specific example of an occlusion catheter is described by Rauker and others in xe2x80x9cOcclusion Devicexe2x80x9d, U.S. Pat. No. 6,475,185 issued Nov. 5, 2002. The occlusion device includes an elongated tubular shaft having an inflatable balloon disposed near the elongate shaft distal end with a proximal seal of a sufficiently small profile to allow a second catheter to pass over the distal occlusion device while the inflatable balloon remains uninflated. One occlusion device includes an elongated fluid displacement rod within the elongated shaft of the occlusion device, providing both a fluid pressure source and a seal.
Controlling the flow and sealing the inflation fluid into the balloon of the occlusion catheter can be challenging. Sell and others have used a valve of an inner tube that is closely fit into an outer tube, as disclosed in xe2x80x9cLow Profile Valve and Balloon Catheterxe2x80x9d, U.S. Pat. No. 6,090,083 issued Jul. 18, 2000. The low-profile inflation valve includes a first thermoplastic tube with at least one region of decreased inner diameter, and a structure, which may be a tube, movably located inside the lumen. The region of decreased inner diameter of the first tube forms a seal with a portion of the structure.
Many medical procedures require that more than one catheter be advanced in and out of a body vessel. Various solutions have been suggested to allow a more rapid, safe, and unobstructed exchange of catheters. Improvements to catheter designs, fittings, valves, other parts of catheters, guidewires, and balloons have been suggested. One proposed improvement in the exchanging of catheters is to have a removable inflation fitting on the inflation tube that supplies fluid to a catheter balloon, as described in xe2x80x9cLow Profile Angioplasty Catheter and/or Guide Wire and Methodxe2x80x9d, Imran et al., U.S. Pat. No. 5,520,645 issued May 28, 1996. The inflation fitting is removable so that the proximal extremity of the catheter is free of obstruction and another balloon catheter can be advanced over the proximal extremity.
Improvements to a balloon occlusion catheter and an associated method are proposed in xe2x80x9cLow Profile Catheter Valve and Inflation Adaptorxe2x80x9d, Zadno-Azizi et al., U.S. Patent Application 20020133117 published Sep. 19, 2002; xe2x80x9cExchange Method for Emboli Containmentxe2x80x9d, Zadno-Azizi et al., U.S. Pat. No. 6,544,276 issued Apr. 8, 2003; xe2x80x9cMethod of Emboli Protection using a Low Profile Catheterxe2x80x9d, Zadno-Azizi et al., U.S. Pat. No. 6,500,166 granted Dec. 31, 2002; and xe2x80x9cLow Profile Catheter Valvexe2x80x9d, U.S. Pat. No. 6,355,014, Zadno-Azizi et al., granted Mar. 12, 2002. The catheter includes a low-profile catheter valve with a movable sealer portion positioned within the inflation lumen of a catheter. The sealer portion forms a fluid tight seal with the inflation lumen by firmly contacting the entire circumference of a section of the inflation lumen. The sealer portion is positioned proximate to a side-access inflation port on the catheter, establishing an unrestricted fluid pathway between the inflation port and an inflatable balloon on the distal end of the catheter. The sealer portion can be moved to a position distal of the inflation port, thereby preventing fluid from being introduced into or withdrawn from the balloon via the inflation port. An inflation adaptor can be used for moving the sealer portion within the catheter to establish or close the fluid pathway between the inflation port and the inflatable balloon.
There is continued interest in improving minimally invasive treatments for vascular stenoses that use various intravascular catheters and associated devices. Of particular interest is the development of an improved occlusion catheter and associated devices and methods that provide faster inflation and deflation time for the occlusion balloon; improved robustness of the guidewire; more controlled advancement of the guidewire and occlusion balloon when crossing lesions in the vessel; greater control of fluoroscopic dye or other imaging fluid; and better visualization of the vessel after temporary occlusion with the occlusion balloon.
Therefore, it is desirable to have an improved blood vessel treatment system and method for treating vessels in the body, providing the abovementioned desirable improvements that increase the utility and performance of the medical devices used during the treatment of a vascular condition.
One aspect of the invention provides a system for treating a blood vessel. The blood vessel treatment system includes a hollow guidewire having a central lumen, an occlusion balloon attached proximate to a distal end of the hollow guidewire, and an inflation catheter slidable over the hollow guidewire. An annular inflation lumen formed between the inflation catheter and the hollow guidewire fluidly communicates with the central lumen of the hollow guidewire. Inflation fluid is allowed to flow through the annular inflation lumen and into a distal portion of the central lumen to inflate the occlusion balloon. The system may include a distal valve coupled to the hollow guidewire to control the flow of inflation fluid between the hollow guidewire and the occlusion balloon.
Another aspect of the invention is an occlusion catheter for blocking flow through a vessel of a body. The occlusion catheter includes a hollow guidewire having a central lumen, an occlusion balloon attached proximate to a distal end of the hollow guidewire, and an inflation catheter slidable over the hollow guidewire. An annular inflation lumen formed between the inflation catheter and the hollow guidewire fluidly communicates with the central lumen of the hollow guidewire, allowing inflation fluid to flow through the annular inflation lumen and into a distal portion of the central lumen to inflate the balloon.
Another aspect of the invention is a method for treating a vascular condition. The method provides an occlusion catheter, which includes a hollow guidewire having a central lumen, an occlusion balloon attached proximate to a distal end of the hollow guidewire, and an inflation catheter slidable over the hollow guidewire. An inflation fluid is injected through an annular inflation lumen formed between the inflation catheter and the hollow guidewire. The inflation fluid flows through an inflation port into a distal portion of the central lumen and through a side port positioned between the central lumen of the hollow guidewire and the occlusion balloon, thereby inflating the occlusion balloon.
The present invention is illustrated by the accompanying drawings of various embodiments and the detailed description given below. The drawings should not be taken to limit the invention to the specific embodiments, but are for explanation and understanding. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof. The foregoing aspects and other attendant advantages of the present invention will become more readily appreciated by the detailed description taken in conjunction with the accompanying drawings.